Abstract
This study of ventilated patients investigated pneumonia risk factors and outcome predictors in 476 episodes of pneumonia (48% community-acquired pneumonia, 24% hospital-acquired pneumonia, 28% ventilator-associated pneumonia) using a prospective survey in 14 intensive care units within Australia and New Zealand. For community acquired pneumonia, mortality increased with immunosuppression (OR 5.32, CI 95% 1.58–17.99, P<0.01), clinical signs of consolidation (OR 2.43, CI 95% 1.09–5.44, P=0.03) and Sepsis-Related Organ Failure Assessment (SOFA) scores (OR 1.19, CI 95% 1.08–1.30, P<0.001) but improved if appropriate antibiotic changes were made within three days of intensive care unit admission (OR 0.42, CI 95% 0.20–0.86, P=0.02). For hospital-acquired pneumonia, immunosuppression (OR 6.98, CI 95% 1.16–42.2, P=0.03) and non-metastatic cancer (OR 3.78, CI 95% 1.20–11.93, P=0.02) were the principal mortality predictors. Alcoholism (OR 7.80, CI 95% 1.20–17.50, P<0.001), high SOFA scores (OR 1.44, CI 95% 1.20–1.75, P=0.001) and the isolation of “high risk” organisms including Pseudomonas aeruginosa, Acinetobacter spp, Stenotrophomonas spp and methicillin resistant Staphylococcus aureus (OR 4.79, CI 95% 1.43–16.03, P=0.01), were associated with increased mortality in ventilator-associated pneumonia. The use of non-invasive ventilation was independently protective against mortality for patients with community-acquired and hospital-acquired pneumonia (OR 0.35, CI 95% 0.18–0.68, P=0.002). Mortality was similar for patients requiring both invasive and non-invasive ventilation and non-invasive ventilation alone (21% compared with 20% respectively, P=0.56).
Pneumonia risks and mortality predictors in Australian and New Zealand ICUs vary with pneumonia type. A history of alcoholism is a major risk factor for mortality in ventilator-associated pneumonia, greater in magnitude than the mortality effect of immunosuppression in hospital-acquired pneumonia or community-acquired pneumonia. Non-invasive ventilation is associated with reduced ICU mortality. Clinical signs of consolidation worsen, while rationalising antibiotic therapy within three days of ICU admission improves mortality for community-acquired pneumonia patients.